This is a love story between a professor and a policewoman. Their dating experience is enhanced with sense and sensibility through the application of interesting physics theories on the investigation of various crime cases.Kingsley King (Raymond Lam) is regarded as the youngest genius in physics and he is appointed as an associate professor in a Hong Kong university. Invited by his good friend Lo Tin-Hang (Kenneth Ma), Senior Inspector of Police at Regional Crime Unit, Pok assists in cracking many mysterious crime cases and he also meets policewoman Chui Siu-Lai (Tavia Yeung) during the process. The rational Kingsley evaluates that he has fallen in love with Lai because of a neurotransmitter called phenethylamine. However, owing to the huge difference in their family background and life value, Kingsley fails to tackle their ever-changing relationship problems with formulas. In the end, due to life changing experiences, Kingsley realizes that love cannot be rationalized and finally admits that his feelings to Siu-Lai are true.On the other hand, the romantic and uninhibited Hang has been maintaining a sex only relationship with the journalist Ling Man-Ka (Bernice Liu). Hang doesn't believe in eternity and he is only looking for sensual pleasure in a woman. However, his belief is suddenly shattered when he learns that Man is going to get married.